Fluid-pressure-operated tool.



PATBNTED JULY 17, 1906. o. H. JOHNSON. FLUID PRESSURE o-PBRATBD TOUL.

:APPLICATION FILED JULY 24. 1902.

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MM2 v zegs.

` Klim Chicago Heights,

. UNITED STATES OHARLES E. JOHNSON,

MESNE` AsSiGNMENTS,

R OF CHICAGO HEIGHTS;

PATENT OEEIOE.

lLLINOIS, ASSIGNORA, BY

TO THE PITTSBURG PNEUMATIC COMPANY, OF

Specification of Letters Patent.

Patented .'niiy 17, 190e.

Application filed July Z4, 19.02.A Seriallo. 116,835.

.To all. whom, it may concern:

Beit known that I, CHARLES H. JOHNSON, a citizen of the United States, residing at county of Cook, State of ois, `have invented a certain new and useful Improvement in Fluid-Pressure-Operated Tools; and -I declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it pertains to make and use the saine, reference being had to the accompanying drawings, which form a part of thi's'specification. f

lMy invention relates in general to fluidressure-operated tools, and more 'particuarly to tools ofthe valveless type.

It is desirable in various uses for which fluid-pressure-operated tools are adapted to have the stroke of the der that theobject wor gaged by iston Avariable in ored upon may beenthe tool at every stroke of the piston, .even though the distance between the Object and the tool does not remain constant. In ramming sand for metal founding, for instance, itis advantageous that the stroke of the rammer should be greater or less according to the comp'actness of the sand by the rammer at each blow. In Working upon uneven surfaces it is necessary that the stroke of the tool should be variable in order that each reciprocation of the piston may'effect the engagement of the tool with theobjective surface.

Another use for fluid-pressure-operated tools in which a variable stroke is of advantage is in undercutting in' mi where the distance between the tool and ti surface cannot be accurately gaged.

N The primary object of my invention is to provide a fluid which the stroke of the piston automatically varies according to the distance between the tool and the surface worked upon. A further object of my invention is' to rovide a iiuid-pressure-operated' tool in w cli the piston reverses immediatel upon'engaging the object without continuing to the limit of its throw.

A still further object of my invention isv to provide a-fluid-pressure-o ,erated tool of the character described whic will be sim le in construction, comparatively inexpensive f in manufacture, and eflicient in operation. The embodiment ofmy invention herein siinilar parts.

engaged e objectivev -pressure-operated tool inv disclosed comprises, generally described, a cylinder having a constantly-open restricted exhaust -port leading from the back end thereof and a vplurality of chambers or reservoirs which are successively charged during the back stroke of the piston and which successively dischar e into the back end of the cylinder during te forward stroke of the piston toward the objective surface. Y

My invention will be more fully described Y hereinafterA with reference to the accompanying drawings, in which the same is emodied in a convenient andpractical form, and in which- Figure 1 is a longitudinal section throu h my invention; Fig. 2, a view similar to Fig. 1, showing the piston in its forward position; and Fig. 3, a cross-sectional view on line `3 3,

imilar reference characters areused in` the several figures of thev drawings to .indicate Reference character A designates a cylinder within an enlarged bore of which islocated a bushing B, centrally spaced byineans of a series of annular partitions b', b2, "b3, b4,`

.65, and b, which are preferably formed integrally with the exterior surface of the bushing. One end of the bushing B engages an annular shoulder A2, formed within the cylinder A between the bores of different diameters therein. The other endof the` bushing is provided with a collar I) of an exterior diameter substantially the same as the intethe larger bore of the cylrior diameter of inder which is engaged and reatined inpro position within the Icylinder by a cy A ead E.

` The cylinder-head E-is secured within they lend of Vthe cylinder A by any suitable meansTas, for instance, a screw-threaded engagement. The cylinder-head is prevented i'rom rotating relatively to the cylinder by 'any suitable means-such, for instance, as vided with an actuating-pin e, -extending through a slot in the end wall of the cylinderhead. The cylinder-head is rovided with a restricted exhaust-port e, w "ch places the interior of the back end of the cylinder in constant communication with the atmosphere.

The annular partitions t', &., divi space between the outer surface of the bushing and the inner surface of the cylinder A e the leri the spring-bolt E,.which is pro-l ICO into a series of chambers or reservoirs a a2,

or the same may a3, a4, c5, a, and a7.' The reservoirs a', &c., are provided with admission-ports c c2, c3, c4, c5, c, and c7, respectively, and also with discharge-ports d', d2, da, d4, d5, de, V and 17. These admission and discharge ports extend through the bushing B, the former being located at the ends of the respective reservoirs toward the forward end of the tool, while the latter are located at the opposite ends of the respective reservoirs-namely, toward the back of the tool.

An annular chamber A is formed in the cylinder A at the point adj acentto the front end of the tool, into which is discharged motive luid from a source thereof. F indicates a screw-threaded sectionorl pipe with which is connected a conduit leadingv from the source Kof motive-Huid supply. The pipe F is screwedinto an opening extending through the wall of the cylinder into the chamber A.

A coupling F2 unites the two sections of pipe F and F. The coupling F2 is preferably in screw-threaded engagement with a portion of the pipe-section F and is provided with a cap F3, which surrounds the ipe-section F yand retains the collar f on the pipe-section F and the inner end of the cap. The two pipe-sections F and F are preierably provided with means for regulating the fiow therethrough of the motive fluid, such means being shown as consisting in a projection f on the end of the pipe-section F hav-- ing ports therethrough, and in arecess formed Within the pipe-section F which serves as a seat against which the projection f may engage. rlhe pro`ectionj" and the cooperating seat are preferably tapered, as shown in Fig. 1.

Located within the cylinder is a piston G, comprising a head G oi a diameter substantially the same as the interior diameter of the ybushing B and oi' a length substantially equal to the distance between 'the adjacent partitions b b2, Sac. The bore of the cylinder A between the shoulder A2 and the chamber A conforms to the interior diameterof the bushing B, while the bore of the cylinder between the chamber A and the 'iront end thereof is of a smaller diameter conforming to the diameter of the piston G between the end thereof and the shoulder g', formed bythe enlarged head G.

rlNhe piston G may be arranged to deliver a blow upon a tool in' any well-lmown ni be secured to a head M tool is designed for means of a pin h when-the ramming purposes.

Any suitable means may be provided for holding the tool when in operation-such, for instance, as a handle A, preferably med integrally with the cylinder A.

The operation of my inventionis as follows: "When the piston is at the 'forward en i il stroke, as shown in Fig. 2, il passes to the chamber A and is ex the atter between the shoulder g, thereby moving the piston toward the left, such mitted by reason of the cylinder being at atmospheric pressure owing to the exhaustport e. The pressure exerted u on the shoulder g moves the piston to the lett, thereby uncovering the admission-port c', leading to the reservoir a, which is consequently charged with pressure. The continued movement of the piston toward the left successively uncovers the admission-ports c2, c3, c, c5, and c, successively charging the reservoirs a?, a?, a4, c5, a", and c. f

When 'the vadmission-ports c7 have been uncovered by the piston-head G", the iluidpressure flows from the reservoir al through the discharge-ports 17, formed through the collar t on the bushing B into the back end of the cylinder which is shown as consisting in a chamber a, 'formed within the cylinder-head F. The discharge-ports C17 being relatively larger than the exhaust-port e, the flow of pressure to the back end of the cylinder is exerted upon the end oi the piston-headA G', which forces the piston to the right, overcoming' the pressure exerted u on the relatively sinall area of the shoul er g. W hen the piston in moving toward the right uncovers the discharge-ports d, the reservoir c is placed in communication with the back end of, the cylinder and adds impetus .to the movement of the piston. The dischargeports d5, d4, d?, d2, and d are successively uncovered during the stroke of the piston toward the object being worked'upon and the reservoirs c5, c4, c3, c2, vand c successively placed in comrninication with the back end oi2 the cylinder.

Should the rammer lil or other tool actuated by th piston Gf engage the objective surtace before the piston has completed its Vforward stroke-that is, before it has reached the position. indicated in Fig. Z-the move- .nent of the piston will be stopped and the pressure in the bach end of the cylinder exh austed through the port e, thereby immediately effecting the movement oi the piston to the lett, owing' to the pressure constantly exerted upon the shoulder g. Should the rammer engage an object when in the position indicated in Fig. i only the pressure admitted to the bach end oiithe cylinder 'from the reservoirs c?, c, and c would exhaiist through the port e, while the pressure would continue stored in the reservoirs ai, at, c2, and a. As the length of the piston-head Cw is greater than the distance between the several partitions t L52, Cac., the pressure which is admitted to ear. reservoir in succession as the piston moves toward the left is prevented irom flowing to the back end of the cylinder until the end ci the piston-head passes the discharge-ports d di", etc., during its 'forward stroke. f'

The flow ci" fluid-pressure to the chamber movement being per- IOO may be regulated by relatively adjusting the two pipe-sections F and F. y turning the coupling F2 so that it moves away from the cylinder the flange f on the pipe-section may moveaway from the pipe-section F2, thereby separating the proj ection` from the seat formed in the pipe-section F, so as to afford increased passage-Way for pressure be- -tween the projection f and the seat formed in the pipe-section F. When the two sections F and F are separated, so as to afford a mailimum passage-way for the Huid-pressure, suc ing the coupling F2 the cylinder.

From the foregoing description it -will be observed that I have invented afluid-pressure-operated tool in which the stroke ofthe piston varies automatically according to .the distancebetween the tool and the objective surface, and as soon as contact is made with the objective surface the piston immediately reverses without continuing its forward stroke.

While I have described more or less precisely the details of wish to be understood as limiting myself thereto, as I contemplate changes in form, the proportion of parts, and the substitution of equivalents, as circumstances may suggest or render expedient, without departing from the spirit of my invention.

Having now fully 'described my invention, what I claim as new, and desire to secure by Letters Patent, is`

1. In a fluid-pressure-operated tool of the valveless type, the combination with a cylinder, of a reciprocating iston therein, said cylinder having motivel uid supply and exhaust ports and passages for automatically terminating the stroke of the piston relatively to the cylinder upon the piston engaging an object.

2. In a iluid-pressure-operated tool of the valveless type, the ycombination with a cylinder, of a reciprocating piston therein, said cylinder having motive-fluid supply and exhaust ports and passages for automatically reversing the movement of the piston upon its movement in one direction bein arrested before it reaches the limit of its stro e.

3. In a uidrassure-operated tool, the combination wit a cylinder, of a reciprocating piston therein, an extension on said piston projecting through the cylinder, said cylinder having motive-fluid supply and exhaust ports and passages for automatically .terminating the stroke of the piston when the end of the extension on the piston engages an object.

4. In a fluid-pressure-operated tool, the combination with a cylinder, of a reciprocating piston therein, an extension on said piston projecting through the cylinder, said cylpassage-way may be restricted by turnso that it will approach construction, I do knot' inder having. motive-fluid supply and exhaust ports and passages for automatically reversing the movement of the piston upon the end of the extension thereof engaging an object.

5. In a uid-pressure-operated tool, the combination with a cylinder having 'a restricted constant exhaust froml the back end thereof, of a reciprocating piston therein, a plurality of reservoirs, and means for successively discharging said reservoirs into the back end of the cylinder.

6. In a fluid-pressure-operated tool, the combination with a cylinder having a restricted constant exhaust from the back end thereof, of a reciprocating piston therein, a plurality of reservoirs', means for successively charging said reservoirs during the throw of a piston away from the work and successively discharging said reservoirs into the back end of the cylinder during the-.stroke of the piston toward the work.

7. In a fluid-pressure-operated tool, the combination with a cylinder having a restricted constant exhaust from the back end thereof, of a reciprocating'piston therein, a plurality of reservoirs, means for successively charging said reservoirs during the throw of the piston away from the work prior to the admission of pressure to the back end of the cylinder and successively discharging said reservoirs into the back end of-the cylinder after the motive-fluid supply has been cut olf therefrom.

8. In a fluid-pressure-operated tool, the combination with a cylinder having a restricted constant exhaust from the back end thereof, of a reciprocating piston therein, a plurality of reservoirs connected with the fluid-pressure supply by the piston during its throw away from the work and successively connected with`the backend of the cylinder by the-piston during its stroke toward the work. 4

9. In a fluid-pressure-operated tool, the combination with a cylinder having a restricted constant exhaust from the back end thereof, a bushing concentrically located Within the cylinder, a series of annular partitions between the cylinder and the exterior of the bushing forming a series of reservoirs, a reciprocating piston successively connecting saidy reservoirs with the source of Huidpressure during its stroke away from the work and successively connecting said reservoirs with the back end of the cylinder during its stroke toward the work.

n testimony whereof I sign this specification in the-presence of two witnesses.

CHARLES H. JOHNSON.

Witnesses:

GEO. L. WILKINSON, C. C. CUNNiNGHAM.

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